Majorana Edge Mode in a Number-conserving Fermi Gas with Tunable p-wave Interaction

<!--StartFragment-->The remarkable exchange properties of Majorana fermions and their potential application in quantum information processing have led to considerable effort to realize topological matters that host these excitations in recent years. In cold atom research, it has been pointed out that coupled chain systems that allow fermion pair hopping between chains can have Majorana ground states even though these system are number conserving. In this work, we show that Majorana ground state can occur in a Fermi gas on a 1D lattice with tunable p-wave interaction, where a pair of fermions can be converted into a close-channel boson and vice versa, thereby allowing fermion pair fluctuation in a single chain. This scheme requires neither spin-orbit coupling nor multi-chain set up and can be implemented easily. We offer evidence of Majorana ground states through DMRG calculations on boson compressibility, entanglement entropy, and edge-edge Majorana fermion correlation. The signature of the Majorana phase can be identified from its momentum distribution. <!--EndFragment-->